Motorists are continuing to risk their lives on the roads by driving erratically, police are warning, following three holiday fatalities in as many minutes.
The Boxing Day accidents have taken NSW's holiday road toll to four and the national toll to 13.
Just before 6.50am (AEDT) on Wednesday, police were called to a two-car collision at Marsden Park in Sydney's northwest.
A male driver died at the scene, while the driver of the other car was taken to hospital suffering from shock.
Minutes later in another accident, two people were killed when the four-wheel drive vehicle they were in rolled on the Hume Highway about 6km north of Holbrook in NSW's south.
A woman and a man died at the scene, while a third passenger was taken to Albury Base Hospital before being airlifted to Melbourne with serious injuries.
A fourth passenger was airlifted from the scene with serious injuries, while two passengers and the driver, a 44-year-old man from the ACT, were taken to hospital with minor injuries.
The accidents have prompted police to warn that drivers are ignoring pleas to take care in the wet conditions with alarming evidence of erratic driving.
"While we have had four fewer fatalities compared to the same period last year, we have seen a significant rise in the number of people injured on our roads," said Traffic and Highway Patrol Commander Assistant Commissioner John Hartley.
Since last Friday, 246 people have been injured in 760 crashes, compared to 640 people injured in 198 crashes during the same period last year.
Supt Hartley said two drivers had been arrested and charged with committing serious offences while driving in heavy rain and poor visibility.
NSW's first holiday period fatality was a 79-year-old woman in a car crash at Mount Ousley, south of Sydney, just after 1pm on Sunday.
The national road toll period runs from 0001 December 23, 2012 until 2359 January 3, 2013, local times, in line with the Australia New Zealand Policing Advisory Board.